1238125 玖、發明說明： 【發明所屬之技術領域】 本發明係關於充氣輪胎，更詳言之，係關於經改善耐偏 磨損性與轉彎性能的充氣輪胎。 【先前技術】 習知，有如：在胎面上朝輪胎圓周方向設置呈直線狀延 伸的複數條主溝，且由該等主溝形成朝圓周方向延伸的肋 (陸部）之充氣輪胎；或者在輪胎圓周方向上，依既定間距 配置著朝輪胎寬度方向延伸的橫溝，並利用主溝與橫溝形 成朝圓周方向延伸的塊狀列（陸部）之充氣輪胎。 在此種充氣輪胎中，例如如圖6所示，係將形成於主溝 1 2間之肋1 3的接地面1 3 X，以在輪胎經線截面中，具有與 形成胎面1 1的輪廓之圓弧C 0的曲率半徑R 0相同之曲率 半徑R1的圓弧C 1所構成。 此種充氣輪胎，於如轉彎行驶之會產生較大轉彎力的使 用條件下，在各肋1 3中，因為接地壓集中於當輪胎安裝在 車輛時構成車輛外側Μ的外側端部1 3 a處，因此該外側端 部1 3 a容易產生局部性磨損的偏磨損現象。特別係從車輛 外側Μ算起第2個陸部1 3 N的外側端部1 3 a處，因為施加 較高的接地壓，因而此端部1 3 a會產生較大的磨損現象， 造成耐偏磨損性大幅惡化的問題。 此外，由於接地壓集中於外側端部1 3 a，陸部1 3之内側 端部1 3 b容易發生浮起或打滑現象。特別係第2個陸部1 3 N 的内側端部1 3 b側發生較嚴重的浮起或打滑，結果潛在有 6 312/發明說明書(補件)/92-12/92124848 1238125 降低轉彎力的問題。 【發明内容】 本發明之目的在於提供一種在如轉彎行驶之會產生較 大轉彎力的使用條件下，可 充氣輪胎。 緣是，達成上述目的之本 朝輪胎圓周方向設有呈直線 該主溝劃分而形成朝圓周方 截面具單一曲率半徑之第1 徵為，將從輪胎安裝於車輛 陸部之接地面，構成為連接 圓弧之至少1個第2圓弧的 越靠車輛外側處的圓弧越小 從上述胎面凹陷入的位置處 上述至少第 2 個陸部的車 d，及面向該車輛外側壁面的 0· 02〜0. 1 ° 依此，可將使财偏磨損性 外側算起第2個陸部的接地 車輛外側處，連接著曲率半 構造，且將此第2圓弧與第 叉點深度 d、與面向車輛外 係，依上述方式進行特定， 靠外側端部從胎面向輪胎内 改善耐偏磨損性與轉彎性能的 發明的充氣輪胎，係於胎面上 狀延伸的複數條主溝，並利用 向延伸的陸部，且由輪胎經線 圓弧構成各陸部接地面；其特 時的車輛外側算起至少第2個 著在車輛外側處鄰接上述第1 構造；上述圓弧的曲率半徑係 ，越靠車輛外側的圓弧越位於 ;且位於車輛最外側的圓弧與 輛外側壁面之交叉點凹陷深度 主溝溝深度D之比d/D設定為 與轉彎性能大幅降低之從車輛 面，形成在習知的第1圓弧靠 徑較小之至少1個第2圓弧的 2個陸部靠車輛外側壁面的交 側壁面的主溝溝深度D間之關 藉此便可有效地使第2個陸部 徑側陷入。 7 312/發明說明書(補件)/92-12/92124848 1238125 所以，因為如轉彎行駛時產生較大轉彎力作用之時，可 將第2個陸部之接地壓分布形成為較習知更均勻的狀態， 因此可避免在其外側端部處出現接地壓提高的狀況發生。 故，不僅可改善耐偏磨損性，同時亦可降低第2個陸部之 内側端部側之浮起或打滑現象，因而可抑制轉彎力的降 低，提昇轉彎性能。 再者，本發明的充氣輪胎，係於胎面上朝輪胎圓周方向 設有呈直線狀延伸的複數條主溝，並利用該主溝劃分而形 成朝輪胎圓周方向延伸的陸部，且由在輪胎經線截面具單 一曲率半徑之第1圓弧構成各陸部接地面；其特徵為，將 從輪胎安裝於車輛時的車輛外側算起至少第2個陸部之接 地面，構成為連接著在車輛外側處鄰接上述第1圓弧的曲 線之構造；上述曲線係形成為越靠車輛外側越從上述胎面 凹陷入的狀態，且上述曲線與上述至少第2個陸部的車輛 外側壁面之交叉點凹陷深度 d，及面向該車輛外側壁面的 主溝溝深度D之比d / D設定為0 . 0 2〜0 . 1。 即便此種構造，在如轉彎行驶之會產生較大轉彎力的使 用條件下，如同上述，仍可改善耐偏磨損性與轉彎性能。 【實施方式】 以下，參照圖式，詳細說明本發明的實施形態。 圖1係顯示本發明的充氣輪胎之一實施形態，在胎面1 上設有沿輪胎圓周方向 T延伸的直線狀複數條（圖中為 3 條）主溝2，並由該等主溝2劃分而形成朝輪胎圓周方向延 伸的肋（陸部）3。另外，C L係指輪胎中心線。 8 312/發明說明書(補件)/92-12/92124848 1238125 從輪胎安裝於車輛時的車輛外側 Μ算起第 2個陸部 3 A 之接地面3 X，如圖2之輪胎經線截面所示，係由具曲率半 徑R1的第1圓弧C1、與在車輛外側處鄰接於其之具曲率 半徑R 2的第2圓弧C 2所構成。第1圓弧C1係與形成胎面 1的輪廓之具有曲率半徑R 0的圓弧C 0 —致，第1圓弧C1 與第2圓弧C 2係鄰接於同一切線上。其他陸部3的各接地 面3 X係由具單一曲率半徑R1的第1圓弧C1所構成。 位於車輛外側（陸部3 A之外側端部3 A 1 )的第2圓弧C 2 之曲率半徑R2，係小於第1圓弧C1的曲率半徑R1，而第 2圓弧C2則構成為越靠車輛外側，從形成胎面1輪廓的圓 弧C0起越呈凹陷的狀態。 第2圓弧C2與第2個陸部3A外側之面向主溝2的車輛 外側壁面3 y之交叉點P的凹陷深度d，與其外側主溝2的 溝深度D之比率d / D為0 . 0 2 S d / D S 0 . 1。另外，所謂交叉 點P的深度d係指圖2中，在位於第2個陸部3 A外側主溝 2兩側的陸部3之接地面3x間晝出切線S，測量從此切線 S至交叉點P正交於輪胎軸方向的長度。此外，所謂主溝2 的溝深度D係指在溝寬中心，測量從溝底2x至切線S正交 於輪胎軸方向的長度。 若依照上述本發明，將大幅影響耐偏磨損性與轉彎性能 降低的陸部3 A之接地面3 X，在習知第1圓弧C1的車輛外 側連接著縮小曲率半徑的第2圓弧C 2，同時將第2圓弧C 2 與陸部3 A之車輛外側壁面3 y的交叉點P深度d規範為如 上述狀態，因為可有效地使外側端部3 A 1較習知胎面位置 9 312/發明說明書(補件)/92-12/921248佔 1238125 更有效地朝輪胎内徑側凹陷入，在較大轉彎力作用之際， 可將接地壓分布成較習知更為均勻化之狀態，因此可避免 接地壓集中於外側端部3 A1處。 所以，因為不僅可改善耐偏磨損性，且可抑制陸部 3 A 的内側端部3A2側產生浮起或打滑現象，因而亦可改善轉 彎性能。 比d / D若小於0 . 0 2，則難以有效地改善轉彎性能與耐偏 磨損性。反之，若超過0 . 1，則無法有效地改善轉彎性能。 圖3所示係本發明充氣輪胎的另一實施形態，第2個陸 部3A的接地面3x乃由曲率半徑為R1，R2，R3之不同的第 1、第2、第3圓弧C1，C2，C3所構成。曲率半徑R1，R2，R3 係第1圓弧C1為最大，位於車輛外側的第3圓弧C 3最小。 依此由3個圓弧C 1，C 2，C 3構成接地面3 X，並將車輛外 側的第3圓弧C3與第2個陸部3A外側之面向主溝2的車 輛外側壁面3 y之交叉點P的凹陷深度d，與面向該車輛外 側壁面3 y的主溝2的溝深度D之比d / D，如同上述地進行 設定，可獲得如同上述的效果。 在本發明中，上述交叉點P的深度d，在與主溝2溝寬 W間的關係中，將其比d / W設定為0 . 0 1 S d / W S 0 . 1 5為佳。 若比d / W低於0 . 0 1，則難以有效地改善轉彎性能與耐偏磨 損性，反之，若超過0 . 1 5，則無法有效地改善轉彎性能。 如圖2實施形態所示，當接地面3x由第1、第2圓弧 C 1，C 2構成的情況時，將圓弧C 1，C 2的曲率半徑R 1，R 2之 比R 1 / R 2設定為2〜1 0為佳。若比R 1 / R 2小於2，轉彎性能 10 312/發明說明書(補件)/92-12/92124848 1238125 的改善效果偏低。反之，若大於1 ο，則轉彎性能與耐偏磨 損性的改善效果偏低。 如圖3所示實施形態，當接地面3χ由第1、第2、第3 圓弧C 1 , C 2，C 3構成的情況時，最好將圓弧C 1，C 2，C 3的曲 率半徑R 1，R 2，R 3之關係，分別將比R 1 / R 2與比R 2 / R 3設定 為2〜1 0。若各比低於2，轉彎性能的改善效果偏低。反之， 若超過1 0，則轉彎性能與耐偏磨損性的改善效果偏低。 在本發明中，上述接地面 3 X亦可由3個以上的複數圓 弧所構成，僅要係由第1圓弧C 1及在其車輛外側處連接之 至少1個第2圓弧C2所構成，且將圓弧曲率半徑設定為越 靠車輛外側之圓弧越小的話便可。此時的交叉點Ρ的深度 d，係位於車輛外側之圓弧與車輛外側壁面3 y的交叉點深 度。 再者，如圖4所示，亦可將在第1圓弧C1靠車輛外側 上曲率半徑朝車輛外側壁面3 y連續減少的曲線4，連接成 鄰接於同一切線上的狀態，並將此曲線4形成為越靠車輛 外側，從形成胎面1輪廓的圓弧CO起逐漸凹陷的狀態。採 用此種曲線4的情況亦同，藉由將曲線4與車輛外側壁面 3y之交叉點P的凹陷深度d及面向車輛外側壁面3y的主 溝2的溝深度D之比d / D，設定為如同上述，便可獲得相 同的效果。 再者，亦可如圖5所示，在第1圓弧C1的車輛内側， 將曲率半徑較第1圓弧C1小的内侧圓弧C 2 ’，設定成鄰接 於同一切線上，並將陸部3a的内側端部3A2之接地面3x 312/發明說明書(補件)/92-12/92124848 η 1238125 部分朝向車輛内側，且從形成胎面1輪廓的圓弧c 0起 凹陷的狀態。 藉此，陸部 3a的内側端部 3Α2在成為如轉彎外側 方向轉彎行駛時，因為可避免接地壓集中於内側端部 上，因此可改善内側端部3A2的耐偏磨損性，而且可 反方向轉彎行驶時的轉彎性能。 圓弧C2’之曲率半徑 R2’與第1圓弧C1之曲率半 間之關係，比R 1 / R 2 ’最好設定為2〜1 0。若比R 1 / R 2 ’低 反向轉彎行駛時的轉彎性能改善效果將偏低，反之， 於1 0，則反向轉彎行駛時之轉彎性能與内側端部3 A 2 磨損性的改善效果偏低。 再者，圓弧C 2 ’與第2個陸部3 A内側之面向主溝2 輛内側壁面3z的交叉點P’的深度d’ ，及其内側主溝 溝深度 D’之比 d’/D’為 O.Ol^d’/D’^O.l 為佳。 d ’ / D ’低於 0 . 0 1，難以有效地改善反向反方向轉彎行 的轉彎性能與内側端部3A2的耐偏磨損性；反之，若 0 . 1，則無法有效地改善反向轉彎行驶時的轉彎性能 在上述實施形態中，雖僅將從車輛外側Μ算起第2 部3Α的接地面3χ形成如上述，但是第3個、第4個 部3之接地面3χ亦可形成相同的構造，僅要至少將對 磨損性與轉彎性能影響較大之第 2個陸部 3Α的接 3 X，設定為上述構造的話便可。 另外，本發明中所謂「主溝 2」係指具有輪胎公稱 之2 %以上的溝寬者，朝較此狹窄之圓周方向延伸的溝 312/發明說明書(補件)/92-12/92124848 逐漸 的反 3Α2 改善 徑R 1 於2, 若大 之耐 之車 2的 若比 駛時 超過 〇 個陸 的陸 耐偏 地面 寬度 :，並 12 1238125 非隸屬此處所言本發明的主溝。 本發明雖在上述實施形態中例示設置肋為陸部的例 子，但是亦可在圖1的胎面花紋上，更沿輪胎圓周方向依 既定間距配置著朝輪胎寬度方向延伸的橫溝，並取代肋而 改設置由朝輪胎圓周方向τ延伸的塊狀列所構成之陸部。 (實施例1 ) 將輪胎尺寸共通設定為2 3 5 / 4 5 Z R 1 7，並分別製作在圖1 所示胎面花紋中，從輪胎安裝於車輛時的車輛外側算起第 2 個陸部之接地面為下述花紋的輪胎：由具有曲率半徑 R 1，R 2之2個圓弧C 1，C 2構成之圖2所示本發明輪胎1;由 具有曲率半徑R1，R2，R3之3個圓弧C1，C2，C3構成之圖3 所示本發明輪胎2;以及由具有曲率半徑R1，R2,R3，R2’之 4個圓弧C 1，C 2，C 3，C 2 ’構成之圖4所示本發明輪胎3。 再者，分別製作：具有圖 6所示構造的習知輪胎；以及 由具有較形成如圖7、8所示胎面輪廓之圓弧C0曲率半徑 R 0更小的曲率半徑R1之圓弧C1構成第2個陸部之接地面 的比較輪胎1、2 ;以及在圖6所示習知輪胎中，將第2個 陸部之外側端部以半徑Rx圓弧截角的圖 9所示比較輪胎 3;以及在本發明輪胎2中，將曲率半徑R1，R2，R3設定為 R 1 > R 2、R 2 < R 3關係的比較輪胎4。 另外，分別製作在具有圖3所示構造的輪胎中，將交叉 點深度d與主溝溝深D之比d / D改變為如表1所示的本發 明輪胎 4〜6 及比較輪胎 5，6。另外，各圓5瓜的曲率半徑 R 0，R 1，R 2，R 3，R 2 ’、及比 d / W，係如表 1 所示。 13 312/發明說明書(補件)/92-12/92124848 1238125 將該等各個試驗輪胎安裝於鋼圈尺寸 1 7 X 8 J J的鋼圈 上，並將空氣壓設定為2 2 0 k P a，經下示測量條件施行轉彎 性能與耐偏磨損性之評估試驗，得到表1所示之結果。 (轉彎性能） 將各試驗輪胎安裝於室内轉鼓測試儀上，並在荷重 4 . 0 k N、行駛速度 1 0 0 k m / h、滑角（s 1 i p a n g 1 e ) 4 °、外傾角 (c a m b e r a n g 1 e ) 3 G之條件下，測量轉彎力（c o r n e r i n g force)，將結果以習知輪胎為1 0 0的指數值進行評估。此 數值越大的話，轉彎力越高，轉彎性能越佳。在此出現1 0 5 以上的顯著效果。 (耐偏磨損性） 將各試驗輪胎安裝於排氣量2升的四輪傳動車上，在1 圈2 . 1 k m的轉彎跑道中行駛1 0圈之後，再測量第2個陸部 的磨損量，將結果採1 0點法進行評估。此數值越大的話， 耐偏磨損性越佳。在此出現7以上之實用上有效的改善效 果。 14 312/發明說明書(補件)/92-12/921248似 1238125 〔Ιϊ 財_台6 g r—Η g § g r—< 1 1 0.12 0.021 s 卜 柳月台6 1000 1000 i g 1 1 r—H CD 0.021 s oo 柳卿台5 1000 1000 1 g t—^ 1 1 0.06 0.021 t—< oo 柳卿台4 g r—( g t—^ i 1 1 0.02 0.021 s 卜 W交糊台5 g H 1000 i 1 1 0.017 0.021 s LO 柳月糊台3 g r-H g r—< § g g 1 0.035 0.021 2 oo 柳月·2 g g 1 g 1 1 0.035 0.021 g t—H oo 柳月·1 g § T—H 8 1 1 1 0.035 0.021 g T—^ 卜 比較輪胎4 1000 1000 g i 1 1 0.035 0.021 s r-H CO tbfe糊台3 g r—H 1000 1 1 1 425 LO ◦· i 0.304 S 1—^ CO W卿合2 1000 i 1 1 1 1 1 1 s 1 "1 CD 交糊台1 1000 CO 1 1 1 1 1 1 s r—H CO 習知輪胎 g r—1 g r-H 1 1 1 1 1 1 g r—< CN1 RO(nni) RKimi) R2(mm) R3(nui) R2，Cim) Rx(mn) § ξ 轉彎慨 而i偏磨損性 200S 寸(ΝΙ(Ν6/(ΝΙ-(Ν6/(φ}®)*^^^®/(Νιε 1238125 由表1中得知，本發明輪胎可有效地改善轉彎性能與耐 偏磨損性。 (實施例2 ) 將輪胎尺寸設定為與實施例1相同，分別製造在上述本 發明輪胎2中，將交叉點d與主溝2溝寬W的比d/W改變 如表 2 的試驗輪胎 1〜5。另外，各圓弧曲率半徑 R0，R1，R2，R3、及比d/D，乃如表2所示。 對該等各試驗輪胎，如同實施例 1，施行轉彎性能與耐 偏磨損性的評估試驗，得到表2所示結果。 [表2] 試驗輪胎1 試驗輪胎2 試驗輪胎3 試驗輪胎4 試驗輪胎5 R0(mm) 1000 1000 1000 1000 1000 R1(mm) 1000 1000 1000 1000 1000 R 2(mm ) 300 300 30 0 300 300 R 3(mm ) 1 00 10 0 1 00 10 0 1 00 d/D 0.035 0.035 0.035 0.035 0.035 d/W 0.008 0.01 0.10 0.15 0.16 轉彎性能 1 03 1 06 10 5 10 5 103 耐偏磨損性 3 7 8 8 7 由表2中得知，最好將交叉點d與主溝2溝寬W的比 d/W，設定在0.01〜0.15之範圍内。 如上述所說明的本發明，藉由將從輪胎安裝於車輛時的 車輛外側算起至少第2個陸部之接地面，形成在習知第1 圓弧車輛外側上，連接著縮小曲率半徑之至少1個第2圓 弧的構造，或者形成在習知第1圓弧車輛外側上，連接著 越靠車輛外側，越從胎面凹陷入的曲線之構造，並將此第 2圓弧或曲線與第2個陸部之車輛外側壁面間的交叉點深 16 312/發明說明書(補件)/92-12/92124848 1238125 度d，及面向車輛外側壁面的主溝溝深D之比d / D，特定在 上述範圍内，藉此在如轉彎行駛之會產生較大轉彎力的使 用條件下，可有效的改善轉彎性能與耐偏磨損性。 (產業上可利用性） 上述具優越效果的本發明，可極有效地使用為安裝在行 駛於轉彎等路況之車輛上的充氣輪胎用。 【圖式簡單說明】 圖1為顯示本發明之充氣輪胎一實施形態的胎面重要部 分正視圖。 圖2為顯示圖1之輪胎經線重要部分放大剖視圖。 圖3為顯示本發明之充氣輪胎另一實施形態的輪胎經線 重要部分放大剖視圖。 圖4為顯示本發明之充氣輪胎再另一實施形態的輪胎經 線重要部分放大剖視圖。 圖5為顯示本發明之充氣輪胎再另一實施形態的輪胎經 線重要部分放大剖視圖。 圖6為顯示習知充氣輪胎的輪胎經線重要部分放大剖視 圖。 圖7為顯示實施例中所採用之比較輪胎1之輪胎經線重 要部分放大剖視圖。 圖8為顯示實施例中所採用之比較輪胎2之輪胎經線重 要部分放大剖視圖。 圖9為顯示實施例中所採用之比較輪胎3之輪胎經線重 要部分放大剖視圖。 17 312/發明說明書(補件)/92-12/92124848 1238125 (元件符號 說明 1 ) 1 胎 面 2 主 溝 4 曲 線 2x 溝 底 3, 3A，1 3 陸 部 3A,13N 第 2 個 陸 部 3 A1 , 13a 外 側 端 部 3A2,13b 内 側 端 部 3 x 接 地 面 3y 車 輛 外 側 壁面 3z 車 輛 内 側 壁面 CO, C2’ 圓 弧 Cl 第 1 圓 弧 C2 第 2 圓 弧 C3 第 3 圓 弧 CL 輪 胎 中 心 線 d 凹 陷 深 度 D 主 溝 溝 深 度 M 車 輛 外 側 P，P’ 交 叉 點 RO, R1,R2, R3 曲 率半 S 切線 T 輪胎圓周方向1238125 Description of the invention: [Technical field to which the invention belongs] The present invention relates to a pneumatic tire, and more specifically, to a pneumatic tire having improved partial wear resistance and cornering performance. [Prior art] Conventionally, it is as follows: a pneumatic tire in which a plurality of main grooves extending linearly are provided on the tread in the tire circumferential direction, and ribs (land portions) extending in the circumferential direction are formed by the main grooves; or In the tire circumferential direction, lateral grooves extending in the tire width direction are arranged at predetermined intervals, and the main grooves and the lateral grooves form a block-shaped row (land portion) of the pneumatic tire that extends in the circumferential direction. In such a pneumatic tire, for example, as shown in FIG. 6, the ground contact surface 1 3 X of the ribs 13 formed between the main grooves 12 is provided in the tire warp cross section to have the same shape as the tread 11. The arc C 1 of the contour has a curvature radius R 0 having the same curvature radius R 1 as the arc C 1. In such a pneumatic tire, under conditions of use, such as when cornering, a large turning force is generated, in each rib 13 because the ground pressure is concentrated on the outer end portion 1 3 a that constitutes the outer side M of the vehicle when the tire is mounted on the vehicle Therefore, the outer end portion 1 3 a is liable to cause a partial wear phenomenon of local wear. In particular, the outer end portion 1 3 a of the second land portion 1 3 N from the outer side M of the vehicle, because a high ground pressure is applied, this end portion 1 a will cause a large abrasion phenomenon, resulting in resistance A problem that the abrasion resistance is significantly deteriorated. In addition, since the ground pressure is concentrated on the outer end portion 1 a, the inner end portion 1 3 b of the land portion 13 is liable to float or slip. In particular, there is a serious floating or slipping on the inner end 1 3 b side of the second land portion 1 3 N. As a result, there is a potential for 6 312 / Instruction Manual (Supplement) / 92-12 / 92124848 1238125 to reduce the turning force. problem. SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire under conditions of use that will generate a large turning force such as driving on a turn. The reason is that the first characteristic of achieving the above-mentioned purpose is to provide a straight line that divides the main groove in the circumferential direction of the tire to form a single radius of curvature toward the circumferential cross-section. At least one of the second arcs connected to the arc is smaller toward the outside of the vehicle, the smaller the arc from the tread is, and the at least the second land portion of the vehicle d, and 0 facing the outer wall surface of the vehicle. · 02 ~ 0. 1 ° According to this, the outer side of the grounded vehicle of the second land can be calculated from the outside of the abrasion of the financial deviation, and the curvature semistructure can be connected, and the depth of the second arc and the fork point d The specific design of the invention with the vehicle-facing system is as follows. The pneumatic tire of the invention, which improves the abrasion resistance and cornering performance from the side of the tire to the inside of the tire by the outer end, is attached to a plurality of main grooves extending in a tread shape. Use the land section extending to form the ground contact surface of each land section by the tire meridian arc; at least the second side of the special vehicle outside the vehicle adjoins the first structure at the vehicle outer side; the radius of curvature of the arc Department, the more outside the vehicle The arc located at the outermost point of the vehicle and the intersection of the outer wall surface of the vehicle and the depression depth of the main groove. The ratio d / D of the main groove and the groove depth D is set to be from the vehicle surface, which greatly reduces the turning performance. At least one of the two land portions of the first arc with a smaller diameter and at least one of the second arcs is intersected by the main groove depth D of the intersection side wall surface of the vehicle outer side wall surface, so that the second land portion can be effectively made. The trail side sinks. 7 312 / Invention Specification (Supplement) / 92-12 / 92124848 1238125 Therefore, if a large turning force is generated during cornering, the ground pressure distribution of the second land can be made more uniform than conventional , So that the situation where the ground pressure is increased at the outer end portion can be avoided. Therefore, not only the uneven wear resistance can be improved, but also the phenomenon of floating or slipping on the inner end portion side of the second land portion can be reduced, thereby reducing the turning force and improving the turning performance. Furthermore, the pneumatic tire of the present invention is provided on the tread with a plurality of main grooves extending linearly in the tire circumferential direction, and the main grooves are divided to form a land portion extending in the tire circumferential direction. The first arc of the tire warp cross section with a single radius of curvature constitutes the ground contact surface of each land portion. It is characterized in that at least the second land contact ground surface is counted from the outside of the vehicle when the tire is mounted on the vehicle, and is configured to be connected. The structure of the curve adjacent to the first arc on the vehicle outer side; the curve is formed in a state of being recessed from the tread toward the vehicle outer side, and the curve and the outer wall surface of the vehicle of the at least second land portion The ratio d / D of the depth d of the intersection and the depth D of the main groove facing the outer side wall surface of the vehicle is set to 0.2 to 0.1. Even with such a structure, under conditions of use such as when cornering, a large turning force is generated, as described above, and the uneven wear resistance and turning performance can be improved. [Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of a pneumatic tire according to the present invention. A plurality of straight main grooves 2 (three in the figure) extending along the tire circumferential direction T are provided on the tread 1, and the main grooves 2 Divided to form ribs (land portions) 3 extending in the tire circumferential direction. In addition, C L means a tire centerline. 8 312 / Invention Manual (Supplement) / 92-12 / 92124848 1238125 The ground plane 3 X of the second land portion 3 A is calculated from the outside M of the vehicle when the tire is mounted on the vehicle, as shown in the tire warp cross section of Figure 2 As shown, it is composed of a first arc C1 having a radius of curvature R1 and a second arc C2 having a radius of curvature R 2 adjacent to the vehicle outside. The first arc C1 is identical to the arc C 0 having a radius of curvature R 0 forming the contour of the tread 1, and the first arc C1 and the second arc C 2 are adjacent to the same tangent line. Each ground plane 3 X of the other land portion 3 is constituted by a first arc C1 having a single radius of curvature R1. The radius of curvature R2 of the second arc C 2 located on the outer side of the vehicle (outside end 3 A 1 of the land 3 A) is smaller than the radius of curvature R1 of the first arc C1, and the second arc C2 is configured to be On the outside of the vehicle, it is in a state of being recessed from the arc C0 forming the contour of the tread 1. The depth d of the intersection point d of the intersection point P between the second arc C2 and the second land portion 3A facing the outer side wall 3 y of the main groove 2 of the vehicle, and the ratio d / D of the groove depth D to the outer main groove 2 is 0. 0 2 S d / DS 0.1. In addition, the depth d of the intersection point P refers to the tangent line S between the ground plane 3x of the land portion 3 on both sides of the main groove 2 on the outside of the second land portion 3A in FIG. The point P is orthogonal to the length in the tire axis direction. The groove depth D of the main groove 2 refers to the length from the groove bottom 2x to the tangent line S orthogonal to the tire axis direction at the groove width center. According to the present invention described above, the ground surface 3 X of the land portion 3 A, which greatly affects the abrasion resistance and the reduction in cornering performance, is connected to the second arc C with a reduced radius of curvature on the outside of the vehicle of the conventional first arc C1. 2. At the same time, the intersection point P depth d of the second arc C 2 and the outer wall surface 3 y of the land portion 3 A is regulated as described above, because the outer end portion 3 A 1 can effectively make the tread position more familiar. 9 312 / Invention Specification (Supplement) / 92-12 / 921248 accounted for 1238125 more effectively recessed into the inner diameter side of the tire. Under the action of a large turning force, the ground pressure can be distributed to be more uniform than conventional In this state, it is possible to prevent the ground pressure from being concentrated on the outer end portion 3 A1. Therefore, not only can the uneven wear resistance be improved, but also the occurrence of floating or slipping on the inner end portion 3A2 side of the land portion 3 A can be suppressed, and the cornering performance can also be improved. If the ratio d / D is less than 0.02, it is difficult to effectively improve cornering performance and uneven wear resistance. Conversely, if it exceeds 0.1, cornering performance cannot be effectively improved. FIG. 3 shows another embodiment of the pneumatic tire of the present invention. The ground contact surface 3x of the second land portion 3A is composed of the first, second, and third arcs C1 having different curvature radii R1, R2, and R3. C2, C3. The curvature radii R1, R2, and R3 are the first arc C1 being the largest, and the third arc C3 located outside the vehicle is the smallest. Based on this, three arcs C1, C2, and C3 constitute the ground plane 3X, and the third arc C3 on the outside of the vehicle and the outer wall surface 3y of the vehicle facing the main trench 2 on the outside of the second land portion 3A are formed. The ratio d / D of the depression depth d of the intersection point P to the groove depth D of the main groove 2 facing the outer wall surface 3 y of the vehicle is set as described above, and the same effects as described above can be obtained. In the present invention, in the relationship between the depth d of the intersection point P and the groove width W of the main groove 2, the ratio d / W is preferably set to 0. 01 S d / W S 0. 15. If the ratio d / W is less than 0.01, it is difficult to effectively improve the turning performance and resistance to uneven wear. On the other hand, if it exceeds 0.15, the turning performance cannot be effectively improved. As shown in the embodiment of FIG. 2, when the ground plane 3x is composed of the first and second arcs C 1 and C 2, the ratio of the curvature radii R 1 and R 2 of the arcs C 1 and C 2 to R 1 / R 2 is preferably set to 2 to 10. If the ratio R 1 / R 2 is less than 2, the turning performance 10 312 / Invention Specification (Supplement) / 92-12 / 92124848 1238125 has a low improvement effect. Conversely, if it is larger than 1 ο, the effect of improving cornering performance and uneven wear resistance is low. In the embodiment shown in FIG. 3, when the ground plane 3x is composed of the first, second, and third arcs C1, C2, and C3, it is preferable to change the arcs C1, C2, and C3. The relationship of the curvature radii R 1, R 2, and R 3 sets the ratio R 1 / R 2 and the ratio R 2 / R 3 to 2 to 10, respectively. If each ratio is less than 2, the effect of improving cornering performance is low. On the other hand, if it exceeds 10, the effect of improving cornering performance and uneven wear resistance is low. In the present invention, the above-mentioned ground plane 3 X may also be composed of three or more plural arcs, and it is only required to be constituted by the first arc C 1 and at least one second arc C 2 connected at the outer side of the vehicle. , And the radius of curvature of the arc is set to be smaller as the arc closer to the outside of the vehicle is smaller. The depth d of the intersection P at this time is the depth of the intersection of the arc located on the outside of the vehicle and the outside wall surface 3 y of the vehicle. Further, as shown in FIG. 4, a curve 4 in which the radius of curvature continuously decreases toward the outer wall surface 3 y of the vehicle on the outer side of the first arc C1 may be connected to a state adjacent to the same tangent line, and this curve may be connected. 4 is formed in a state of being gradually recessed from the arc CO forming the contour of the tread 1 toward the outside of the vehicle. The same applies to the case where such a curve 4 is used, and the ratio d / D of the recessed depth d at the intersection point P between the curve 4 and the vehicle outer wall surface 3y and the groove depth D of the main groove 2 facing the vehicle outer wall surface 3y is set as As above, the same effect can be obtained. Alternatively, as shown in FIG. 5, the inside arc C 2 ′ having a radius of curvature smaller than that of the first arc C1 may be set inside the vehicle of the first arc C1 so as to be adjacent to the same tangent line, and the land The grounding surface 3x 312 of the inner end portion 3A2 of the portion 3a / Invention Specification (Supplement) / 92-12 / 92124848 η 1238125 partially faces the inside of the vehicle and is recessed from the arc c 0 forming the contour of the tread 1. With this, when the inner end portion 3A2 of the land portion 3a is turning in a direction such as when turning outside, the ground pressure can be prevented from being concentrated on the inner end portion, so the abrasion resistance of the inner end portion 3A2 can be improved, and the reverse direction can be reversed. Turning performance when cornering. The relationship between the curvature radius R2 'of the circular arc C2' and the curvature half of the first circular arc C1 is preferably set to 2 to 10. If it is lower than R 1 / R 2 ', the turning performance improvement effect when driving on a reverse turn will be lower. On the contrary, at 10, the turning performance when driving on a reverse turn and the abrasion resistance improvement effect of the inner end portion 3 A 2 On the low side. Furthermore, the depth d 'of the intersection P' between the arc C 2 ′ and the inner side of the second land portion 3 A facing the inner side wall surface 3z of the 2 main ditch, and the ratio d '/ of the inner main ditch depth D ′ / D 'is preferably O.Ol ^ d' / D '^ Ol. d '/ D' is less than 0.1, it is difficult to effectively improve the turning performance of the reverse turn and the abrasion resistance of the inside end portion 3A2; on the contrary, if it is 0.1, it is not effective to improve the reverse Turning performance during cornering. In the above-mentioned embodiment, although only the ground plane 3x of the second section 3A is formed from the vehicle outer side M as described above, the ground plane 3x of the third and fourth sections 3 may also be formed. For the same structure, it is only necessary to set at least the connection 3 X of the second land portion 3A, which has a large effect on abrasion and turning performance, to the above structure. In addition, the "main groove 2" in the present invention refers to a groove having a groove width of 2% or more of the tire nominal length, and the groove extending toward the narrower circumferential direction 312 / Invention Specification (Supplement) / 92-12 / 92124848 gradually The anti-3Α2 improvement path R 1 is at 2, and the Ronald Car 2 has a land width of more than 0 land when driving, and 12 1238125 does not belong to the main ditch of the invention described herein. Although the present invention exemplifies the example in which the rib is a land portion in the above embodiment, a lateral groove extending in the tire width direction may be arranged on the tread pattern of FIG. 1 at a predetermined distance along the tire circumferential direction, instead of Instead, a land portion composed of a block-shaped column extending in the tire circumferential direction τ is provided instead. (Example 1) The tire size was set to 2 3 5/4 5 ZR 1 7 in common, and each was made in the tread pattern shown in FIG. 1, and the second land portion was counted from the outside of the vehicle when the tire was mounted on the vehicle. The ground contact surface is a tire having the following pattern: the tire 1 of the present invention shown in FIG. 2 composed of two arcs C 1 and C 2 having a radius of curvature R 1 and R 2; and the tire 1 having a radius of curvature R 1, R 2 and R 3 3 arcs C1, C2, C3 composed of the tire 2 of the present invention shown in FIG. 3; and 4 arcs C1, C2, C3, C2 'having a radius of curvature R1, R2, R3, R2' The structure of the tire 3 of the present invention is shown in FIG. 4. Furthermore, a conventional tire having the structure shown in FIG. 6 is separately produced, and an arc C1 having a radius of curvature R1 having a smaller radius of curvature R0 than the arc C0 of the tread profile shown in FIGS. 7 and 8 is formed. Comparative tires 1 and 2 constituting the ground contact surface of the second land portion; and in the conventional tire shown in FIG. 6, the outer end portion of the second land portion is compared with that shown in FIG. Tire 3; and in the tire 2 of the present invention, a comparative tire 4 having a relationship of the curvature radii R1, R2, R3 as R 1 > R 2, R 2 < R 3 is set. In addition, in the tires each having the structure shown in FIG. 3, the ratio d / D of the intersection depth d to the main groove depth D was changed to the tires 4 to 6 of the present invention and the comparative tire 5 shown in Table 1, 6. In addition, the curvature radii R 0, R 1, R 2, R 3, R 2 'of each circle and the ratio d / W are shown in Table 1. 13 312 / Invention Specification (Supplement) / 92-12 / 92124848 1238125 Install each of these test tires on a steel ring of steel ring size 1 7 X 8 JJ, and set the air pressure to 2 2 0 k P a, An evaluation test of turning performance and uneven wear resistance was performed through the measurement conditions shown below, and the results shown in Table 1 were obtained. (Turning performance) Each test tire was installed on an indoor drum tester, and the load was 4.0 k N, running speed 100 km / h, slip angle (s 1 ipang 1 e) 4 °, camber angle ( Under the condition of camberang 1 e) 3 G, cornering force is measured, and the result is evaluated with an index value of a conventional tire of 100. The larger the value, the higher the turning force and the better the turning performance. Significant effects above 1 0 5 appear here. (Uneven wear resistance) Each test tire was mounted on a four-wheel-drive vehicle with a displacement of 2 liters, and after 10 laps on a 2.1 km turn course, the abrasion of the second land portion was measured. The results were evaluated using the 10-point method. The larger this value is, the better the abrasion resistance is. This results in a practically effective improvement effect of 7 or more. 14 312 / Invention Specification (Supplement) / 92-12 / 921248 like 1238125 [Ιϊ 财 _ 台 6 gr—Η g § gr— < 1 1 0.12 0.021 s Bu Liu platform 6 1000 1000 ig 1 1 r--H CD 0.021 s oo Liu Qingtai 5 1000 1000 1 gt— ^ 1 1 0.06 0.021 t— < oo Liu Qingtai 4 gr— (gt— ^ i 1 1 0.02 0.021 s Bu Wujitai 5 g H 1000 i 1 1 0.017 0.021 s LO Liuyue paste table 3 g rH gr— < § gg 1 0.035 0.021 2 oo Liuyue · 2 gg 1 g 1 1 0.035 0.021 gt—H oo Liuyue · 1 g § T—H 8 1 1 1 0.035 0.021 g T- ^ Bu compare tires 4 1000 1000 gi 1 1 0.035 0.021 s rH CO tbfe paste 3 gr-H 1000 1 1 1 425 LO ◦ i 0.304 S 1- ^ CO W Qinghe 2 1000 i 1 1 1 1 1 1 s 1 " 1 CD Pasting Station 1 1000 CO 1 1 1 1 1 1 1 sr—H CO Conventional tire gr—1 g rH 1 1 1 1 1 1 gr— &CN; RO (nni) RKimi) R2 (mm) R3 (nui) R2, Cim) Rx (mn) § ξ Turns and the wear resistance is 200S inch (ΝΙ (Ν6 / (ΝΙ- (Ν6 / (φ) ®) * ^^^ ® / (Nιε 1238125) It is known from Table 1 that the tire of the present invention can effectively improve cornering performance and uneven wear resistance. (Example 2) The tire size It was set to be the same as in Example 1, and manufactured in the above-mentioned tire 2 of the present invention, respectively, and the ratio d / W of the intersection point d to the groove width W of the main groove 2 was changed as in Test tires 1 to 5 in Table 2. In addition, each arc The curvature radii R0, R1, R2, R3, and ratio d / D are shown in Table 2. For each of these test tires, an evaluation test of turning performance and uneven wear resistance was performed as in Example 1, and Table 2 was obtained. [Table 2] Test tire 1 Test tire 2 Test tire 3 Test tire 4 Test tire 5 R0 (mm) 1000 1000 1000 1000 1000 R1 (mm) 1000 1000 1000 1000 1000 R 2 (mm) 300 300 30 0 300 300 R 3 (mm) 1 00 10 0 1 00 10 0 1 00 d / D 0.035 0.035 0.035 0.035 0.035 d / W 0.008 0.01 0.10 0.15 0.16 Turning performance 1 03 1 06 10 5 10 5 103 Partial wear resistance 3 7 8 8 7 It is known from Table 2 that the ratio d / W of the intersection point d and the groove width W of the main groove 2 is preferably set within a range of 0.01 to 0.15. As described above, the present invention forms the ground contact surface of at least the second land portion from the outside of the vehicle when the tire is mounted on the vehicle, and is formed on the outside of the conventional first arc vehicle, and is connected to the reduced radius of curvature. A structure of at least one second arc, or a structure formed on the outside of a conventional first arc of a vehicle, and connected to a curve that is recessed from the tread the more the vehicle is outside, and the second arc or curve is formed Depth of intersection with the vehicle outer wall surface of the second land portion 16 312 / Invention Specification (Supplement) / 92-12 / 92124848 1238125 degrees d, and the ratio of the main groove depth D facing the vehicle outer wall surface d / D Specifically, within the above range, under the use conditions that will generate a large turning force such as driving on a turn, the turning performance and uneven wear resistance can be effectively improved. (Industrial Applicability) The above-mentioned advantageous effects of the present invention can be extremely effectively used as a pneumatic tire mounted on a vehicle driving on a road condition such as a turn. [Brief Description of the Drawings] FIG. 1 is a front view showing an important part of a tread of an embodiment of a pneumatic tire of the present invention. FIG. 2 is an enlarged sectional view showing an important part of the tire warp line of FIG. 1. FIG. Fig. 3 is an enlarged cross-sectional view of an important part of a tire warp showing another embodiment of the pneumatic tire according to the present invention. Fig. 4 is an enlarged cross-sectional view showing an important part of a tire warp according to still another embodiment of the pneumatic tire of the present invention. Fig. 5 is an enlarged sectional view showing an important part of a tire warp according to still another embodiment of the pneumatic tire of the present invention. Fig. 6 is an enlarged sectional view showing an important part of a tire warp of a conventional pneumatic tire. Fig. 7 is an enlarged sectional view showing an important part of a tire warp of the comparative tire 1 used in the embodiment. Fig. 8 is an enlarged sectional view showing an important portion of a tire warp of the comparative tire 2 used in the embodiment. Fig. 9 is an enlarged sectional view showing an important part of a tire warp of the comparative tire 3 used in the embodiment. 17 312 / Invention Manual (Supplement) / 92-12 / 92124848 1238125 (Description of component symbols 1) 1 Tread 2 Main groove 4 Curve 2x Groove bottom 3, 3A, 1 3 Land section 3A, 13N Second land section 3 A1, 13a Outer end 3A2, 13b Inner end 3 x Ground plane 3y Vehicle outer wall surface 3z Vehicle inner wall surface CO, C2 'Arc Cl 1st arc C2 2nd arc C3 3rd arc CL Tire centerline d Depression depth D Main groove depth M Outside of vehicle P, P 'Intersection RO, R1, R2, R3 Half curvature S Tangent T Tire circumferential direction
312/發明說明書(補件)/92-12/92124848 18 1238125 W 溝寬312 / Invention Manual (Supplement) / 92-12 / 92124848 18 1238125 W groove width
312/發明說明書(補件)/92-12/92124848 19312 / Invention Specification (Supplement) / 92-12 / 92124848 19